Antennas

[Wrightwood]

Toolman mentioned that he was looking for something that is a little more omni-directional and I wonder if will see this is in his antenna farm in the future?

[clint]

Hey! Who let that guy use gaffs on  a pine tree?

[Toolman]

Toolman mentioned that he was looking for something that is a little more omni-directional and I wonder if will see this is in his antenna farm in the future?

 Great idea.....could you imagine how big that would need to be at HF frq's

[KWBoy]

Great idea.....could you imagine how big that would need to be at HF frq's

Could you imagine how big of a hissy fit everyone would have if you had something like that but for HF freq's lol! 

[clint]

Looks like a modern artists idea of a Dandelion seed.

[Toolman]

Looks like a modern artists idea of a Dandelion seed.

That's a good one Clint...

 So what type of matching network would be used given a 50ohm feedline for this array? It's not a discone, but has almost the same properties, so what is it? Odd I don't see any feed line so what now? What frq. is it being used at? Id say pick any frq. you like and pick a matching network to make it function. It appears to be in the 1.8-2.4 ghz. range but lets say you wanted an array like this on 2mtrs.

 Would we use a Beta Match, Cirquit Q, Delta match, Direct? Gamma match? Hairpin match, Omega match, Pi network, RLC network, L-C network,S-P Transmatch, Stub match, T-Match, or Transmatch?

 Get out them calculators.. A little hint, this array would work almost like stacking yagis at a 1/4 wavelength apart. Another hint....by construction, does it look circular polarized? Does it resemble a poor mans parabolic? It's certainly not  Helix either....but could it work like one?

 Or.... is it a photo shop toy and has no means of functional operation at all. You decide 

[kew]

When using a magnetic mount antenna on a car, how do you get the cable from the antenna inside the car to the radio without deforming (crushing) the coax?

Note to Kathy & Jeff - don't tell me to leave the window or the door open.

[RobertW]

When using a magnetic mount antenna on a car, how do you get the cable from the antenna inside the car to the radio without deforming (crushing) the coax?

Note to Kathy & Jeff - don't tell me to leave the window or the door open.

This is definately the disavantage of a Magnetic Antenna.  While the coax will get squished a little, the weather seal of the door usually provides enough room that the coaxial can handle it and won't be permanently damaged, though I'm sure Clint will inform us that it definately has an effect on the performance.

BTW, if you leave the coax in place for a long time your weather stripping gets "deformed" as well making it susceptible to leaking.  But then "it NEVER rains in Southern California".

[kew]

Thanks Robert. The biggest problem I'm having with my radio is a wife that says, "You are NOT drilling a hole in my car!!!" 

[RobertW]

Thanks Robert. The biggest problem I'm having with my radio is a wife that says, "You are NOT drilling a hole in my car!!!" 

I think we're married to the same lady!  MY wife says that.

[CA5th]

When I used a mag mount I was fortunate that the manufaturer had left a hole (plugged with a rubber plug) in the body under the trunk lid.  I ran the cord through the plug and did not have a problem.  The cord ran in the space between the the trunk lid and body to the mag mount.

My wife did not want an antenna on the car but after it was mounted she found it was real easy to find the car in a crowded parking lot.  That might work with people that are a little reluctant.

[lagomorphmom]

Must be an X-chromosome deal, I'm the same way. HOWEVER, there are other acceptable solutions.

When I had my Celica, I used a lip mount antenna in the middle of edge joining the rear window (some people mount them on the side lip). Had a great Diamond antenna on it and could easily open the lid without banging paint with the antenna. It has nylon pads to keep the paint safe, and since it doesn't move, I think there's less issue with scratches from dirt/dust than the mag mount. It comes with a cap if you want to take/leave off the antenna. Not all are made equal, I'll try to find mine to share the model and then you can compare. I really liked this solution for a sedan/coupe car. I'll leave y'all to calculate the radiation into the passenger compartment through the glass for 2m-440, see what you think....

On my Jeep & currently on my Tacoma shell I use a window mount because I park in a structure at work. Mike says the Larson is the best, comes with the antenna. As you'd expect, not quite as good as a direct connection but only a short step down, works very well.

[clint]

explain to your wife that a mag mount vibrating around on the micro dust under the mount will do more damage to her car than a hole will. She will end up with a dull sanded spot on her roof which will be much bigger than an NMO mount.

And Bob is right. Deforming coax changes the impedance and can be very bad for your radio.


A trunk lip mount as Kerin suggested is an okay alternative, as is a through the glass. Although they receive poorly. Larsen makes the best one.

[ChattyCathy]

Are there any easy-to-follow instructions to make a J-pole?  I've looked online, but I can't seem to find anything relatively easy (for the non-electrician-type person).

[clint]

No matter what kind you build you will have to have tools and know how to solder. There were about ten built at our workshop yesterday some by folks who had never soldered before. There are lots of on line plans, many of them don't work. I can give you plans for the ones that I know do work.

[RobertW]

No matter what kind you build you will have to have tools and know how to solder. There were about ten built at our workshop yesterday some by folks who had never soldered before. There are lots of on line plans, many of them don't work. I can give you plans for the ones that I know do work.

Clint,

Please email me the plans for those you know do work.

Thanks!

[ChattyCathy]

Soldering - I guess I don't have the right tools.  Bummer I couldn't make the workshop - I got bombarded with work on Sunday.  Where can I purchase a J-pole?  We'd like to put it in the tree over our house.

No matter what kind you build you will have to have tools and know how to solder. There were about ten built at our workshop yesterday some by folks who had never soldered before. There are lots of on line plans, many of them don't work. I can give you plans for the ones that I know do work.

[Wrightwood]

Here it is RobertW:

http://www.wrightwoodcalif.com/ham/ClintFoldableJPole.pdf

Or this graphic uses the same dimension for the 2 meter flexible jpole:

[SkierBob]

[lagomorphmom]

Here's some conversation on the Palmdale guy as well as a posting from him...

Amateur Radio Creates Static in Community:
http://www.eham.net/articles/17401